Potato (Solanum tuberosum L.) is one of the most valuable crops in the world, ranked as the 4th most important food crops after rice, wheat and maize. Currently, a variety of techniques for producing potato minituber have been investigated, including soilless aeroponic, hydroponic and deep-water culture systems. However, minitubers potato production in the greenhouse from apical rooted cutting grown coco-peat under a photoperiod and nutritional - shock system is a new and creative idea. The use of diazotrophic bacteria such as Azospirillum brasilense demonstrates a positive effect on nitrogen availability, a primordial element for the development of this plant. Therefore, this study aimed to evaluate the growth and minitubers yield in a potato cultivar inoculated with A. brasilense at different doses. The experiments were conducted in controlled greenhouse on concrete raising beds with dimensions of 10 m x 1 m x 0.3 m. The study revealed that the concentration of A. brasilense at different doses significantly affected the height growth, leaves growth, leaves area growth, the average number of tubers plant-1, standard tuber and potato seed minituber yield. The treatment applied with A. brasilense at a concentration of 200 mL m-2 after planting gave the highest yield of potato minitubers (277.8 tubers m-2).

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Currently, a variety of techniques for producing potato minituber have been investigated, including soilless aeroponic, hydroponic and deep-water culture systems. However, minitubers potato production in the greenhouse from apical rooted cutting grown coco-peat under a photoperiod and nutritional - shock system is a new and creative idea. Therefore, the objective of the study was to optimize the effect of photoperiod and nutritional-shock on growth performance and yield of first generation potato tuber production of potato plants. Potato variety ‘Atlantic’ was treated under 5 photoperiod – (8 h/day, 9 h/day, 10 h/day, 11 h/day and natural light) under nutritional-shock process with reducing N concentration in nutrient solution (0;25%; 50%;75% and 100%), the growth stage of plant to conduct nutritional-shock (30, 35, 40, 45 and 50 DAT), the implementation time of nutritional-shock (12, 24, 48 and 60 hours) and the combination of photoperiod (9 h/day, 10 h/day) and nutritional-shock (75%, 100%) on the formation and development of minitubers. The study revealed that photoperiod at 10h/day showed the best result with 7.4 tubers/ plant and 569.7 tubers m-2. The number of tuber stolons, average number of tubers and tuber yield was directly proportional to the decreasing in N concentration in the nutrient solution, in which the highest was the 100% reduction in N concentration with 9.3 tubers/plant, higher than the control treatment 300%. The nutrient shock treatment at 30 DAT in 48 ours gave the best tuber production efficiency. There was a strong interaction between photoperiod and nutritional-shock on the formation and yield of potatoes (10.6 tubers/plant, 308 tubers m-2).

Plant density and fertilization are key practices for improving the fruit quality and yield of vegetables grown in greenhouses. The experiment was performed to investigate the effects of density and fertilization on the fruit yield and quality, economic efficiency of Solanum lycopersicum L. at Duc Trong district of Lam Dong province. The density (50,000; 33,000; 25.000 plants ha-1) and the fertilizer rates (240N – 100P2O5 – 275K2O; 300N – 125P2O5 – 344K2O; 360N – 150P2O5 – 413K2O kg and 420N – 175P2O5 – 482K2O kg ha-1) were studied in a completely randomised split plot design with three blocks. The fertilizer rate (420N – 175P2O5 – 482K2O kg ha-1) was produced the highest height (562.39 cm), fruit setting rate (69.87%), number of fruit per plant (95.65 fruits), average fruit weight (106.37 g), fruit yield (441.11 tons ha-1) and marketable fruit yield (204.31 tons ha-1). The density (25,000 plants ha-1) gave the highest fruit setting rate (75.35%), number of fruit per plant (94.84 fruits), average fruit weight (113.24 g), individual fruit yield (10.02 kg per plant) and fruit yield (501.17 tons ha-1). The combination of density (25,000 plants ha-1) and fertilizer rate (420N – 175P2O5 – 482K2O kg ha-1) have the highest fruit yield (613.5 tons ha-1), marketable fruit yield (223.91 tons ha-1) and rate of return (2.44). In addition, this combination was the best density and fertilizer level management strategy for greenhouse-grown Lahay 334 tomato cultivar in Lam Dong province, Vietnam.